I just bought a 2005 F150 Supercab XLT and the 4 wheel drive doesn't work. They told me that the diagnostics pointed to the BCM ? Are the two systems related ?

 

Please define "4 wheel drive doesn't work." There are many parts that have to work together with the end result being that the front wheels get driven. Some pretty simple parts can fail and cause the front wheels not to get driven. For example:

Does the ESOF Motor run when shifting into / out of 4 wheel drive?

Does the Transfer Case shift?

Do the front Half Shafts turn?

Do the IWE's lock?

 

I havent had a chance to do any troubleshooting yet, just wondered if it was even possible to be the BCM like they told me?

 

That's so far down the list that I wouldn't even consider it just yet. Always go for the basics / easy stuff first. I'm sure replacing the truck would fix it too!